Research Interests

Methods are being developed to analyze trace impurities on the surface
of silicon wafers through the use of Total Reflection X-ray Fluorescence
(TXRF). In collaboration with Sematech member companies, a facility at
the Stanford Synchrotron Radiation Laboratory (SSRL) has been developed
to measure transition metal contamination on silicon surfaces at levels
as low as 1e-6 monolayer (~1e8atoms/cm2). The research
program includes development of new measurement technologies as well
as collaborations with industry.

Understanding the relationship between the atomic and
electronic structure of semiconductor interfaces and their electrical properties.

Various electron spectroscopies (x-ray photoelectron spectroscopy, photoelectron
diffraction, NEXAFS, x-ray standing waves, STM) are used to study the atomic
and electronic structures of novel semiconductor materials and semiconductor
iinterfaces. The ultimate goal of this research is to understand the physical
and electrical properties of these materials through an understanding of
their electronic structure. Systems currently being studied are passivated
silicon surfaces prepared using wet chemical techniques. Photoemission
spectroscopy is used to determine the bonding between the passivating layer
and the silicon surface as well as the adsorption characteristics of the
adsorbate, i.e., does the adsorbate bond as a molecule or does it dissociate
upon bonding.